Actually I found there is no power supply for the logic and the motor of
the HD. Linus told (if I didn't get him wrong) the voltage for the HD
comes directly from the batteries. So actually I try to follow the path
of it.

Does anybody know where I should be able to measure those 5V without
dissoldering the two main PCBs? In especial I'd be interested in the
routing of the small PCB where the ATA 44-pin is attached.